This video (in French language) will help you understand the possibilities of GPS Extrem'Sud by Gandini with a real situation. A journey made in the summer of 2011 in the hinterland of Nice, round the top of Authion, at the entrance to Mercantour National Park. It includes two modes of navigation, OnRoad to reach the programmed path from the French Riviera Coast, and OffRoad to complete the course itself. Although it has not been conducted in Morocco, this demonstration is fully compliant, especially with regard to the various functions of the device, you will find that after passing the Strait Gibratar.
(in French language)